Fuse or breaker sizing for 24v

[MrNatural22]

What size fuse or breaker would be appropriate for use on a 24v 100ah LiFePo to a 24v 2000w pure sine inverter for RV use where a small microwave (700w/1100w use) or a 1200 w coffee maker would be the largest Draw?

 

[MrNatural22]

Ok Ok disregard......I figurered it out..... 2000W / 24V = 83.33 x 1.25= 104.1625A or in other words a good quality 125amp breaker will work.?

 

[Ampster]

good quality 125amp breaker will work

Assuming your wire is sized for that Amplerage. The 125 % rule applies to continuous load and you have to ask yourself are you going to be running your inverter full tilt boogie or maybe 1500 Watt continous at most.

 

[MrNatural22]

Assuming your wire is sized for that Amplerage. The 125 % rule applies to continuous load and you have to ask yourself are you going to be running your inverter full tilt boogie or maybe 1500 Watt continous at most.

Yeah 1500w would be what my max usage would be 99% of the time only using a small micro and gotta make that coffee in the morning. I'm using 1/0 g pure copper cables from batteries to breaker to inverter and thru the 350a shunt. The pst 2000 24 Samlex shouldn't break a sweat.

 

[Fred S]

I would size the battery-to-inverter cable at #4 or larger (100a, copper wire), and use a 100a fuse or breaker.

2000w/24v + 20% inverter loss and safety = 100a.
The larger microwave will draw around 1100w/24v + 15% inverter losses = 53 amps from the battery.

 

[Fred S]

Oops, already answered.

 

[MrNatural22]

Oops, already answered.

? No worries...It's all good. Thanks.

 

[MrNatural22]

Plan is to hard wire inverter into the existing shore power box to power the 110v outlets installed. I'm thinking Installing a TS into the system so both sources aren't working together just a bit foggy on connections on the TS. It would need to be connected to the inverter ac out and the shore ac in?
An automatic TS would work. Can a Manual switch from shore to inverter or inverter to shore be a cheaper option? Or a problem?
Any wise input on this??

 

[ghostwriter66]

Plan is to hard wire inverter into the existing shore power box to power the 110v outlets installed. I'm thinking Installing a TS into the system so both sources aren't working together just a bit foggy on connections on the TS. It would need to be connected to the inverter ac out and the shore ac in?
An automatic TS would work. Can a Manual switch from shore to inverter or inverter to shore be a cheaper option? Or a problem?
Any wise input on this??

Manual would be significantly cheaper ... i can't see any real issue .... You might want to re-read your second post (#2) for phrasing -- LOL

 

[MrNatural22]

Oops ? that just did not sound right.
I fixed it.
Mama woulda soaped up my mouth on that one. LOL

 

[MrNatural22]

Manual would be significantly cheaper ... i can't see any real issue .... You might want to re-read your second post (#2) for phrasing -- LOL

I could live without an automatic TS.?
Any suggestions or recommendations on a proper switch for manual use??

 

[ghostwriter66]

I could live without an automatic TS.?
Any suggestions or recommendations on a proper switch for manual use??

Its more a personal taste ....I think that I have done everything from literally LARGE knife switches to the circular ones to - well you name it ... some of the switches have been $40 and some $400 -- it all depends on your taste and budget .. just ,ake sure you get one thats rated for your AMP -- thats about the only thing that can go wrong ...I sort of like the ones that are circular and just have a 1 / off / 2 on them .. check Amazon ... i think they run about $40 ... lots of the marine type guys seem to use them .... but they make a solid "clunk" between shifting so there is no mistake in them .. I will look tomorrow at work - I think it begins with a P or something

 

[ghostwriter66]

and found it ...

https://www.amazon.com/gp/product/B00144B6AE/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

and

Amazon.com : attwood 14230-3 Single Pole 4-Way Selector Marine Battery Switch, One Size : Battery Switch For Boat : Sports & Outdoors

Amazon.com : attwood 14230-3 Single Pole 4-Way Selector Marine Battery Switch, One Size : Battery Switch For Boat : Sports & Outdoors

www.amazon.com

 

[MrNatural22]

and found it ...

https://www.amazon.com/gp/product/B00144B6AE/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

and

Amazon.com : attwood 14230-3 Single Pole 4-Way Selector Marine Battery Switch, One Size : Battery Switch For Boat : Sports & Outdoors

Amazon.com : attwood 14230-3 Single Pole 4-Way Selector Marine Battery Switch, One Size : Battery Switch For Boat : Sports & Outdoors

www.amazon.com

Thanks @ghostwriter66 but problem I see is those switches shown are for DC only. I am needing to switch 120v AC 15-20amps between shore power to inverter as needed.

 

[MrNatural22]

I searched Amazon for a 120v simple transfer switch for between shore and inverter power and found this critter.
looks to be what I need ?

 

[Ampster]

Or this, depending on how handy you are with wiring.

https://www.amazon.com/dp/B00004WLKA/ref=cm_sw_r_cp_apa_i_qfd-EbRBJCCX9

 

[MrNatural22]

Looks also like a great option?

Not the greatest wirer unless lm looking at a wiring diagram as a guide.
cant seem to find wiring info on that switch.

 

[Zil]

Fuses (or breakers) protect wires. I use the largest fuse to protect the capacity of the cable. Goal; reduce voltage drop while preventing the insulation from melting. My inverter pulls 150 amperes through 2/0 cable rated for 330 amperes. I have a 300 amp fuse at the positive bus bar.

 

[ghostwriter66]

Looks also like a great option?

Not the greatest wirer unless lm looking at a wiring diagram as a guide.
cant seem to find wiring info on that switch.

If you go to Google ... and type in ... how to wire a double pole double throw switch ... and go to images .. there are a tons of schematics ... also YOUTUBE has a lot of how to videos ...

BUT with that said -- the Xantrex is cheap and automatic .. win-win

 

[ghostwriter66]

Thanks @ghostwriter66 but problem I see is those switches shown are for DC only. I am needing to switch 120v AC 15-20amps between shore power to inverter as needed.

sorry about that - i thought you were looking at battery to inverter switches for some reason

 

[mapguy525]

One thing to consider on the manual vs. auto transfer switch; When manually transferring power all electronic type devices are going to reboot at power transfer. A good quality auto transfer switch will sync power sources prior to power transfer such that most electronic devices won't reboot.
IMO the transfer device -if installed on shorepower input, should be sized for the shorepower capabilities; 30 amp rv system needs a minimum 30 amp rated device. 50 amp RV needs a minimum of a 50 amp rated device.

On you inverter fusing question; what does the Owners Manual call for? Make sure you account for power boost function and surge function requirements. Manufacturers like Samlex, Victron, Xantrex have detailed information on fuse sizing and conductor sizing to handle the inverter capability. The budget market inverter manufacturers don't give much if any information regarding fuse/conductor sizing needed to make their device fully function.

 

[mapguy525]

If you go to Google ... and type in ... how to wire a double pole double throw switch ... and go to images .. there are a tons of schematics ... also YOUTUBE has a lot of how to videos ...

BUT with that said -- the Xantrex is cheap and automatic .. win-win

Xantrex unit is fine for branch circuit use. Not really sized for use on a 30 amp capable shorepower input circuit.

 

[ghostwriter66]

One thing to consider on the manual vs. auto transfer switch; When manually transferring power all electronic type devices are going to reboot at power transfer. A good quality auto transfer switch will sync power sources prior to power transfer such that most electronic devices won't reboot.
IMO the transfer device -if installed on shorepower input, should be sized for the shorepower capabilities; 30 amp rv system needs a minimum 30 amp rated device. 50 amp RV needs a minimum of a 50 amp rated device.

On you inverter fusing question; what does the Owners Manual call for? Make sure you account for power boost function and surge function requirements. Manufacturers like Samlex, Victron, Xantrex have detailed information on fuse sizing and conductor sizing to handle the inverter capability. The budget market inverter manufacturers don't give much if any information regarding fuse/conductor sizing needed to make their device fully function.

You could always run both FEEDS into a UPS and then have the UPS power the circuit -- so during switch overs nothing goes down since technically everything is powered by the UPS ... -- BUT no such thing as a inexpensive 30A UPS - probably looking at $1.2K to start ....

 

[mapguy525]

You could always run both FEEDS into a UPS and then have the UPS power the circuit -- so during switch overs nothing goes down since technically everything is powered by the UPS ... -- BUT no such thing as a inexpensive 30A UPS - probably looking at $1.2K to start ....

that would be a complex reaction solution to a very common RV world transfer device situation.